Fluid operated wrench for tightening or loosening a threaded connector

Abstract

 fluid operated wrench for tightening or loosening a threaded connector (located in socket 49) without turning the wrench around, includes a cylinder (5) in which a piston with a piston rod (12) is reciprocatable and a ratchet arrangement mounted in a transmission support (2). A reversable transmission arrangement in the transmission support portion (2) is interconnected between said piston rod (12) and the ratchet arrangement to drive the latter in one or the opposite direction during reciprocation of the piston in the cylinder (51. The socket (49) is coaxially connected to the ratchet arrangement for engaging a thread connector to be turned, whereby during turning of the threaded connector in one direction a force is created turning the support (2) in the opposite direction. A reaction member (46) is adjustably connected to a reaction support portion (3) to abut against a stationary object adjacent to one or the other side of the threaded connector to be turned depending on the direction of turning of the latter.

Description

[0001] Various fluid-operated wrenches, including drive means In the form of a cylinder and a piston reciprocating therein which drive, via a ratchet arrangement, a shaft to which a socket is connected for engaging a threaded connector to tighten or loosen the same, are known in the art. One drawback of these known constructions is, that when the wrench has to be used for loosening instead of tightening a threaded connector, the whole wrench has to be turned around through 180° which makes for a cumbersome operation.

[0002] Since during driving of the ratchet arrangement and the socket connected thereto in one direction, a force is created tending to turn the whole wrench in the opposite direction, most of the fluid-operated wrenches include also a reaction member, for instance adapted to abut against a threaded connector adjacent to the one to be turned, to counteract this force. If the threaded connector has to be turned in its tightening direction, this reaction member has to abut against one side of the adjacent threaded connector and if the wrench is used for loosening a threaded connector, the reaction member has to abut against the other side of the adjacent connector. But this is not possible in all cases, since sometimes if two flanged tube members have to be connected by the threaded connectors, the threaded connectors are so close to the outside surface of the tubes so that the reaction member cannot be placed between the adjacent threaded connector and the projecting tube.

[0003] Another drawback of known fluid-operated wrenches is that the overall height of the wrench is rather large so that its application in certain constructions is extremely difficult and sometimes even impossible.

[0004] This invention seeks to provide a reversible fluid-operated (e.g. a cylinder/piston powered) wrench with a universally applicable reaction member. As most cylinder/piston powered ratchet wrenches are constructed to turn and ratchet in just one direction, the wrench has to be turned over to provide a turning action in the opposite direction. There is only one prior art cylinder/ piston powered ratchet wrench known to the applicant that permits, upon disassembly and turning of the ratchet mechanism, an active ratchet turn in both directions. This wrench, was invented by Wilmeth in 1978, however, it requires, the use of a reaction socket that fits over the adjacent nut. This, in turn, means that for every flange with a different nut size, a different reaction socket has to be used which is not just costly, but at the same time, is confusing for the operator. In addition, the reaction socket of this known wrench is attached to the housing portion which contains a pivotally attached cylinder. The present invention makes the necessity of special sockets obsolete by using a reaction member which abuts against the outside of either one of the adjacent nuts as a result of its universal reaction member, which is attached around the reaction portion located around the drive member.

[0005] Preferred embodiments of the present invention provide a fluid-operated wrench in which the overall height of the wrench is reduced to a minimum, but which can be used for tightening or loosening a threaded connector without turning the wrench around.

[0006] A further aim of the present invention is to provide the wrench with an adjustable reaction member which can be used even in situations where the reaction member cannot be placed between an adjacent threaded connector and the outer surface of a flanged tube.

[0007] With these and other aims in view, which will become apparent as the description proceeds, the fluid operated wrench for tightening or loosening a threaded connector without turning the wrench around comprises fluid operated cylinder and piston means, ratchet means, transmission means interconnected between said cylinder and piston means and said ratchet means to drive the latter in one direction during movement of said piston means, means connected to said ratchet means for engaging a threaded connector to be turned, and a reaction member to absorb the reaction force generated on turning the threaded connector in said one direction.

[0008] The wrench is characterised in that the transmission means is reversible whereby the ratchet means can be driven in the opposite direction also, and in that the reaction means is adjustably fitted on the wrench to permit it to abut against a stationary object adjacent to either side of the threaded connector to be turned depending on the direction of turning of the threaded connector.

[0009] A specific embodiment of wrench in according with the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a side view of the wrench,

Figure 2 is a section taken along line 2-2 of Figure 4 through the wrench shown in Figure 1,

Figure 3 is a view of the underside of the wrench showing the reaction support portion, but with the reaction member omitted therefrom, and

Figure 4 is a front view of the wrench, with certain details omitted.

[0010] Referring to the drawings, it will be seen that the illustrated wrench comprises support means including, as best shown in Figure 3, a drive support portion 1, a transmission support portion 2 arranged symmetrically with respect to said drive support portion 1 but extending angularly with respect thereto, and a reaction support portion 3 extending perpendicular to one side from the transmission support portion. The support portions 1, 2 and 3 are operatively connected to each other. As illustrated, the transmission support portion 2 is connected by screws 4 to the drive support portion 1 whereas the reaction support portion 3 is shown as being integral with and projecting to one side of the transmission support portion 2. Other arrangements for connecting these portions together may, of course, also be employed.

[0011] A fluid-operated cylinder and piston means, best shown in Figure 2, is mounted on the drive support portion 1 extending substantially in the direction of the latter. This fluid-operated cylinder and piston means includes a cylinder 5 provided at the end thereof facing the drive support portion 1 with a pair of trunions 6 projecting to opposite sides of the cylinder and being pivotally engaged in appropriate bores 7 in the drive support portion 1. A piston 8 is slidably located in the cylinder 5 for movement between a forward and a return stroke. Means 9 and 10 are connected to the outer end of the cylinder 5 for feeding pressure fluid in a known manner, not specifically shown in the drawing, to opposite sides of the piston 8 to reciprocate the latter along the forward and a return strokes. The piston 8 is provided, in the usual manner, with annular seals 11 properly sealing the outer surface of the piston against the inner surface of the cylinder 5. A piston rod 12 is connected, for instance by a nut 13, to the piston 8, but on the other hand, the piston rod 12 may also be integrally connected to the piston 8. If the piston rod is connected by the nut 13 as shown in Figure 2, an additional annular seal 14 is provided around the portion of the piston rod 12 extending through the piston 8. A further annular seal 15 is provided at the end of the cylinder 5 facing the transmission support portion 2 and one of the fluid feeding means opens at 16 adjacent to the end seal 15, whereas the other of the fluid feeding means passes through an opening 17 in the rear wall 5' of the cylinder 5.

[0012] The transmission support portion 2 comprises two side walls 18, 18', best shown in Figure 4, preferably integral with a top wall 18". A pair of lever means 20 and 20', best shown in Figures 2 and 4 are arranged parallel and closely adjacent to the side walls 18 and 18' of the transmission support portion 2. These lever means 20 and 20' are pivotally connected to the outer end 12' of the piston rod 12 by a pin 21 extending through an appropriate bore 22 in each lever means 20, 20'. The lever means 20, 20' are in the region of their lower ends freely pivotable on a shaft 23 which extends through respective bores in the lever means as well as through respective bores in the side walls 18 and 18' and with an end portion thereof extending beyond one of the side walls, here shown as the side wall 18. The outer end portion of the shaft 23 is preferably of square cross-section and is adapted to receive a standard socket 49 for engagement with the head of a threaded connector or a nut to be turned. A sprocket 24, best shown in Figure 2 is fixed to the shaft 23 for rotation therewith by being, for instance, connected by a key 25' thereto. A member 26 is pivotally mounted on the lever means 20 and 20' between the upper ends of the latter and the sprocket 24. Two curved pawls 27 and 27', integrally connected to the member 26, project to opposite sides thereof and define, with the sprocket 24, ratchet means for incrementally rotating the shaft 23. A switching arrangement 28 is provided to bring a selected one of the two pawls into engagement with the teeth of the sprocket 24. The illustrated switching arrangement comprises a manually operated handle 29 pivoted by a pivot pin 30 on the lever means 20 and 20' and ending in a sleeve 31. A compression spring 32 is housed in the sleeve 31 and acts on a plunger 33 guided in the sleeve 31 and extending to a pin 34. The pin 34 has its lower end engaged in a groove 35 provided on the upper surface of the pawl 27 of the member 26. If the handle 29 is tilted about the pivot pin 30 in the clockwise direction, so that the lower end of the pin 34 will engage the opposite end of the groove 35, the pawl 27 will be lifted out of engagement with the teeth of the sprocket 24, while the pawl 27' will be brought into engagement therewith. In this way, the wrench can be used in a very simple manner for tightening or loosening a threaded connector without turning the wrench around.

[0013] The lever means, 20, 20', together with the member 26 with its pawls 27, 27', form transmission means transmitting a drive force from the piston 12 to the sprocket 24.

[0014] The wrench illustrated also includes a holding pawl 36 engaging the teeth of the sprocket 24 and pivoted at one end thereof by trunions 37 respectively projecting to opposite sides and located in grooves 38 provided in a boss 39 projecting to one side of the transmission support portion 2 between the side walls 18 and 18' thereof. A first leaf spring 40 extending around the lower end of the holding pawl 36 and abutting with opposite ends against the lever means 20 and 20' holds the holding pawl 36 in engagement with the teeth of the sprocket 24. A second leaf spring 41 extending about the outer surface of the first leaf spring 40 is anchored at one end on a pin 42 extending between the side plates 18 and 18', whereas the other end of the second spring 41 terminates within a coil spring 43 housed in a bore 44 and compressed therein by a screw 45 in this bore.

[0015] If the sprocket 24 is to be driven by the pawl 27', the holding pawl 36' has of course to be reversed to extend in the downward direction. This can be accomplished by loosening the screw 45 and turning the sprocket 24 in the appropriate direction, so that the trunions 37 at the end of the holding pawl 36' will slide upwardly in the groove 38 and the holding pawl will then extend somewhat in the dowwnward direction, thereafter the screw 45 is again tightened, to bring the free end of the holding pawl 36' into proper engagement with the teeth of the sprocket 24.

[0016] As mentioned before, the switching arrangement 28 can bring either the pawl 27 or the pawl 27' into engagement with the teeth of the sprocket 24, so that during the reciprocation of the piston 8 in the cylinder 5, a nut or the like engaged in the socket 49 may be turned either in tightening or loosening direction. Since a nut to be loosened may be corroded and require, for loosening the same, a greater force than for proper tightening of the same, the wrench illustrated is constructed in such a manner that during engagement of the pawl 27 with the teeth of the sprocket 24, that is when the ratchet is turned in the loosening direction of a right-hand thread, the pressure fluid will act through the opening 17 in the end wall 5' of the cylinder on the full face of the piston 8 during the forward stroke of the piston 8 in the cylinder 5, whereas if the pawl 27' is engaged with the teeth of the sprocket 24, the pressure fluid flowing through the opening 16 will act on the annular face of the piston 8 reduced by the cross-section of the piston rod as the piston 8 moves in the rearward direction.

[0017] Since during turning of a threaded connector in one direction a reaction force is created tending to turn the support means in the opposite direction, the wrench of the present invention includes also a reaction member to abut against a stationary object adjacent to the threaded connector to be turned. If the threaded connectors are used to connect two flanged tube member this reaction member may abut against the outer surface of one of the flanges. Since the wrench of the present invention may be used for tightening or loosening a threaded connector without turning the wrench around, the reaction member has to be adjustable, since the aforementioned reaction force will tend to turn the support means in the one or the other direction. For this purpose a splined reaction support portion 3 projects normal to the outside of the side wall 18 of the transmission support portion 2 coaxial with the shaft 23, which in turn extends through and beyond an opening in this reaction support portion. The reaction member 46 comprises a first splined annular portion 47 engaging with the splines of the reaction support portion 3 and a second portion integral with the first portion and extending laterally from the latter substantially in the direction of the axis of the ratchet 24, to abut, for instance on the outer surface of the flange in which the threaded connectors are provided. The reaction member 46 is thus adjustable to any desired position depending on the direction in which the reaction force will act.

[0018] The wrench illustrated is characterised by a simple and sturdy construction of relatively small overall height. Its drive means are cylinder and piston means which are simpler in construction than rotary drive means and which require no gears for transmitting the drive from a rotary drive means to the socket to be engaged with the threaded connector to be turned. Nevertheless, the wrench illustrated is provided with a simple switching arrangement which permits the use of the wrench in tightening 43 loosening a threaded connector without turning the wrench around. In conjunction with this feature, the wrench includes also an adjustable reaction member which can be easily brought into the correct position depending on whether the wrench is used for tightening or loosening a connector,

[0019] It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of fluid operated wrenches differing from the types described above.

[0020] While the invention has been illustrated and described as embodied in a fluid operated wrench, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing from the scope of the following claims.

Claims

1. A fluid operated wrench for tightening or loosening a threaded connector without turning the wrench around, comprising fluid operated cylinder and piston means (5, 8), ratchet means (24, 26), transmission means (20, 21, 28) intermediate said cylinder and piston means (5, 8) and said ratchet means (24, 26) to drive the latter in one direction during movement of said cylinder and piston means (5, 8), means (23, 49) connected to said ratchet means (24, 26) for engaging a threaded connector to be turned, and a reaction member (46) to absorb the reaction force generated on turning the threaded connector, characterised in that the transmission means (20, 21, 28) is reversible whereby the ratchet means (24, 26) can be driven in the opposite direction also, and in that the reaction member (46) is adjustably fitted (via 3) on the wrench to permit it to abut against a stationary object adjacent to either side of the threaded connector to be turned depending on the direction of turning of the threaded connector.

2. A wrench as claimed in claim 1, characterised in that the cylinder and piston means (5, 8) comprises a piston (8) reciprocatable in a cylinder (5) between forward and a return strokes, and in that a piston rod (12) is connected at one end to said piston (8) and projects with its other end beyond one end of said cylinder (5).

3. A wrench as claimed in claim 2, characterised in that the piston rod (12) is fixedly attached at said one end to the piston (8) and wherein the cylinder (5) is pivotally connected (6, 7) to another portion (2) of the wrench housing the transmission and ratchet means.

4. A wrench as claimed in any preceding claim,. characterised in that the reversible transmission means comprises lever means (20, 20') connected at one end to said cylinder and piston means (5, 8) and mounted adjacent to the other end for pivotal movement about the axis of the ratchet means (24, 26) and an adjustable pawl member (26) mounted on said lever means (20, 20') intermediate the ends of the latter and constructed to drive a sprocket (24) in one or in the opposite direction during pivotal movement of the lever means (20, 20').

5. A wrench as claimed in claim 4, characterised in that the adjustable pawl member (26) comprises a member mounted at its opposite ends on said lever means (20, 20'), tiltable about an axis parallel to the rotating axis of the sprocket (24), and a pair of pawls (27) fixed to said member (26) and projecting to opposite sides of the latter, and in that a manually operated switching means (28) is provided for bringing one or the other of said opposite pawls (27) into engagement with the teeth of said sprocket (24).

6. A wrench as claimed in any preceding claim, characterised in that a holding pawl means (36') is provided for preventing turning of the ratchet means (24, 26) in a direction opposite to that in which it is driven, said holding pawl means (36') being constructed to be switched over when the drive of said ratchet means (24, 26) is changed from said one to the opposite direction and vice versa.

7. A wrench as claimed in any preceding claim, characterised in that the wrench comprises a reaction support portion (3) to permit the reaction member to be fitted thereto, the reaction support portion being coaxial with the turning axis of the connector engaging means (23).

8. A wrench as claimed in claim 7, characterised in that the reaction member (46) comprises a first portion (47) extending about the reaction support portion (3) and a second portion (48) integral with the first portion (47) and extending laterally from the latter generally in the direction of the turning axis of the connector engaging means (23).

9. A wrench as claimed in claim 8, characterised in that the reaction support portion (3) is in the form of a splined member integral with a portion (2) of the wrench housing the transmission means and said first portion (47) of said reaction member (46) has splines cooperating with said splined reaction support portion (3).

10. A wrench as claimed in any preceding claim, characterised in that the cylinder and piston means (5, 8) comprises a cylinder (5), a piston (8) reciprocatable in the cylinder (5) and means for alternatingly feeding and discharging pressure fluid to and from opposite ends of the piston (8) to reciprocate the latter along a forward and a return stroke, the pressure fluid impinging during the forward stroke on the full area of one side of the piston (8), whereas the fluid impinging during the return stroke of the piston (8) impinges on the side of the latter to which the piston rod (12) is connected and thus on an annular piston face having a smaller area than the full area thereof, the reversible drive means being arranged so that when a threaded connector is to be turned in its loosening direction, the pressure fluid will act during the forward stroke of said piston on the full piston face to thereby turn the ratchet means (24, 26), whereas when the reversible drive means has to turn the threaded connector in its tightening direction, the pressure fluid will act during the return stroke of the piston (8) on the annular piston face.

Drawing